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mina [271]
2 years ago
11

What do you use to write on a blackboard? ​

Physics
2 answers:
Archy [21]2 years ago
6 0

Answer:

Chalk

Explanation:

please mark as brainliest

Elina [12.6K]2 years ago
4 0

Answer:

Chalk, expo markers. Why?

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If Abdul pedals his 20 kg bike with a force of 100 N, what will the bike’s acceleration be? The formulas above may be helpful in
Scorpion4ik [409]

Answer:

5 m/s/s

Explanation:

F = ma

100 = 20a

100/20 = a

a = 5 m/s/s

4 0
3 years ago
A wedge with a mechanical advantage of 0.78 is used to raise a house corner from its foundation. If the output force is 7500 N,
Zigmanuir [339]

Answer:

5850

Explanation:

MA = Force out/ Force in

.78 = out/ 7500

.78 times 7500 = input

6 0
2 years ago
A satellite of mass m is in a circular orbit of radius R2 around a spherical planet of radius R1 made of a material with density
Amiraneli [1.4K]

Answer:

a)      K = 2/3 π G m ρ R₁³ / R₂ ,  b) U = - G m M / r

Explanation:

The law of universal gravitation is

     F = G m M / r²

Part A

Let's use Newton's second law

     F = m a

The acceleration is centripetal

     a = v² / R₂

     

      G m M / R₂² = m v² / R₂

      v² = G M / R₂

They give us the density of the planet

    ρ = M / V

    V = 4/3 π R₁³

    M =   ρ V

    M =   ρ 4/3 π R₁³

    v² = 4/3 π G  ρ R₁³ / R₂

    K = ½ m v²

    K = ½ m (4/3 π G ρ R₁³ / R₂)

    K = 2/3 π G m ρ R₁³ / R₂

Part B

Potential energy and strength are related

     F = - dU / dr

     ∫ dU = - ∫ F. dr

The force was directed towards the center and the vector r outwards therefore there is an angle of 180º between the two cos 180 = -1

    U- U₀ = G m M ∫ dr / r²

    U - U₀ = G m M (- r⁻¹)

We evaluate for

    U - U₀ = -G m M (1 / r_{f} -  1 /r_{i})

They indicate that for ri = ∞     U₀ = 0

    U = - G m M / r

6 0
3 years ago
Russell bradley carried 207 kg of bricks 3.65 m up a ladder. If the amount of work required to perform that task is used to comp
MrRa [10]

Answer:

Explanation:

Work done in carrying bricks

mgh

= 207 x 9.8 x 3.65

-= 7404.4 J

Work done in compressing gas

PΔV

Pressure x change in volume

1.8 x 10⁶ ΔV = 7404.4

ΔV  = 7404.4  / 1.8 x 10⁶m³

= 4113.33 x 10⁻⁶ m³

= 4113.33 cc

8 0
3 years ago
Read 2 more answers
Jimothy is riding his bike to his friend's house. He decides to see how fast he can go, and starts pedaling as hard as he can. H
german

Answer:

Final velocity, V = 11.5m/s

Explanation:

Given the following data;

Initial velocity, U = 2.5m/s

Acceleration, a = 1.5m/s²

Time, t = 6secs

To find the final velocity, we would use the first equation of motion

V = U + at

Substituting into the equation, we have

V = 2.5 + 1.5*6

V = 2.5 + 9

Final velocity, V = 11.5m/s

6 0
2 years ago
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